The CEO of Kinder Morgan says events in recent days have reinforced his concerns about the viability of the Trans Mountain expansion project.

"It's become clear this particular investment may be untenable for a private party to undertake. The events of the last 10 days have confirmed those views," Steve Kean said on a conference call Wednesday.

The political wrangling around the project has significantly escalated since Kinder Morgan halted work earlier this month, saying British Columbia's obstruction efforts have created too much uncertainty for the company and setting a May 31 deadline to find a resolution.

Alberta Premier Rachel Notley has responded by pushing to restrict oil shipments to B.C. and promising financial backing for the project, while B.C. Premier John Horgan has stood firm in his opposition. Saskatchewan has also said it will look to restrict oil shipments to B.C.

"We've pointed out there are significant differences between governments, and those differences are outside of our ability to resolve," Kean said on the call.

Prime Minister Justin Trudeau flew back to Ottawa on Sunday to meet with both premiers to try solve the impasse, but the meeting ended with no clear resolution.

Trudeau said after the meeting that the federal government was prepared to financially back the pipeline, and he had directed Finance Minister Bill Morneau to sit down with the company to discuss the matter.

Kean confirmed on the call that discussions have begun, but said he was not going to make any details public until a definite agreement has been reached or the discussions have ended.

He said the company also continues to meet with stakeholders ahead of the May 31 deadline, and is looking for a way forward for the project.

Kean said investment questions around the Trans Mountain pipeline shouldn't be taken as a wider comment on investing in Canada.

"We have invested in Canada and British Columbia, as well as Alberta, and we expect to continue investing," he said.